NARRATIVE This STTR Phase I proposal details the rationale and the research plan for the development of a novel liquid embolizing agent composed of the genetically engineered protein polymer, SELP (silk-elastinlike protein)-815K, to embolize cerebral aneurysms. The SELP embolic would reduce the risk of aneurysm rupture while minimizing the risk of recanalization after treatment and providing a platform for delivering newly developed drugs or cell therapies directly to the aneurysmal sac. This work will result in an embolic that can potentially improve aneurysm healing, deliver therapeutics locally, and reduce the risks associated with the embolization of cerebral arteries.